The invention relates to a method for sorting mail items with the aid of characteristics on the mail item surface and by using a sorting machine, which sorts the items on the basis of these scanned and recognized characteristics.
One or more of the following problems can occur when sorting mail items on the basis of characteristics on the mail item surface to a high number of sorting directions:
Sorting machines with the required number of separation racks are not available;
Not enough space is available for correspondingly large sorting machines;
Correspondingly large sorting machines are too expensive.
According to prior art, mail items are therefore distributed as follows to a large number of sorting directions by using smaller sorting machines:
Variant 1:
Several (n pieces) smaller sorting machines are used. The first machine is used for a presorting according to a sorting plan A with n-1 target directions. The presorted mail items are then sorted for the final direction in the additional n-1 sorting machines, based on sorting plans 1 to n-1. The total number of possible sorting lines equals the sum of the separation racks of machines 2 to n. The use of this variant has advantages only if the volume of mail items is high enough, so that the n machines are used to capacity. If this is not the case, another variant offers itself:
Variant 2:
For this, all n sorting plans, meaning the presorting plan and the final sorting plans, are executed one after another on a single sorting machine. In the first step, all mail items are therefore presorted according to plan A for the respective final sorting plan and are then stored (e.g. in boxes). In additional sorting runs, the mail items are again fed to the sorting machine from the mail item storage magazines and are sorted for the final sorting directions.
The disadvantages of variant 2 include:
All mail items must first pass through step 1 before the step 2 can be started. Thus, the preparation must be completed before the final sorting can start. This is a problem with respect to the postal operation since mail items generally arrive distributed throughout the day at the sorting center. The final sorting in this case cannot be started until very late, wherein the time required for the final sorting process is long.
The last mail items sorted to the final direction are those of sorting plan n-1. Thus, any of the following possible processing steps (such as shipping, delivery or the like) for these mail items cannot take place until all other mail items have been sorted.
The intermediate storage of the mail items between presorting and sorting to the final direction is unfavorable for reasons of space and organization.
It is the object of the invention to create a sorting process, which permits a continuous sorting to the final direction on a single sorting machine, wherein the number of final directions is higher than the number of separation racks for the machine.
This object is solved according to the invention by simultaneously presorting and sorting to the final direction on only one sorting machine. This method has the following advantages:
The total required processing time is shorter than if the sorting plans are processed one after another since the full separation rack capacity is used continuously.
The scope of required mail item storage magazines is small.
The sorting machine can be supplied continuously with new, unsorted mail items.
In an advantageous embodiment according to the invention, all incoming mail items are presorted. The mail items presorted for the active final sorting plans are again fed into the sorting machine. The mail items are distributed according to presorting and final sorting plans, either through manual input of the operator or through marking the mail items during the presorting, which then allows an automatic assignment to a final sorting plan during the second sorting run. A bar code is used, for example, for this marking, which can be printed on as address code after the address is read and recognized.
Based on another advantageous embodiment according to the invention, incoming mail items, which must be sorted according to the respectively active final sorting plans, are sorted immediately without presorting. The remaining mail items are presorted.
According to yet another embodiment of the invention, the mail items respectively sorted to the final direction, with the associated activated final sorting plans, are advantageously selected on the basis of the mail item frequency or based on operational aspects.
Furthermore, it is advantageous if separate input stations are provided for mail items that are unsorted and items that are presorted and fed back. In that case, the input station for the unsorted mail items is provided with an address reader for recognizing the address and a code printer for printing on a code that marks the recognized address. Also, the input station for presorted mail items that are fed back is provided only with a code reader. In addition to saving costs, this also permits an automatic feeding of the mail items into the machine; e.g. the presorted mail items are fed back only if unsorted mail items are not available at the moment.
It is furthermore favorable if knowledge of the actual statistical distribution of mail items to the sorting directions is used to modify the final sorting plans. As a result, frequently used separation racks can be placed in locations, for example, which are favorable from a transport-technical point of view, or possibly existing reserve separation racks can additionally be assigned to high use directions to avoid or delay an overflow in the sorting compartments.